This invention relates generally to control modules for air conditioning systems and, more particularly, to heat sink cooling of electronic components in a control module mounted to an outdoor coil apparatus.
As part of an outdoor, or condensor coil apparatus, it is generally necessary to have certain control elements for controlling the various included elements such as the compressor and fan motors. The control elements are generally packaged in a control box which is located on or near the outdoor coil assembly.
Heretofore, the control modules have primarily included mechanical and electro-mechanical devices. Since such devices generated relatively little heat, it was not necessary to make any provision for cooling of the various components since the required cooling effect occurred naturally by way of conduction and convection.
With the advent of solid state control devices and the use of such devices in air conditioning control modules, greater amounts of heat are generated within the control box. For example, in inverter controlled variable speed compressor applications, a plurality of relatively large transistors are used to perform the switching functions, thereby resulting in substantial amounts of heat being generated. In order to protect those components from damage, this heat must be dissipated.
A common method of cooling electronic components is that of using a heat sink to cause the heat to be conducted relatively quickly from the electronic components to the heat sink, which has a relatively large surface area that can be cooled rather quickly by convection. Such a heat sink must therefore be thermally connected to the electronic components while at the same time being exposed to the cooling medium such as the surrounding ambient air. The heat sink must therefore be incorporated into the control box in such a way as to achieve these purposes. At the same time, however, for purposes of manufacture, it is desirable to simplify the manner in which the heat sink is mounted to the control box. Accordingly, the applicants first choices were to mount the heat sink on the side of the control box or on the top portion thereof. The applicants discovered that in each of these locations the degree of heat dissipation to the ambient air was insufficient.
In order to enhance the heat dissipation from a heat sink, it has become common practice to provide a plurality of ribs or fins to thereby increase the surface area and the rate at which heat is transferred to the surrounding air. Because of the well known "chimney affect", it is common to mount a heat sink such that the fins are aligned vertically to thereby cause an enhanced flow of cooling air vertically upwardly across the surface thereof.
It is therefore an object of the present invention to provide, in an air conditioning system, a control box having electronic components therein and having improved heat dissipation characteristics.
Another object of the present invention is the provision in an air conditioning control box, a heat sink mounting arrangement which is simple in design and effective in dissipating the required amount of heat.
Yet another object of the present invention is the provision in an air conditioning control box having electronic components therein, for adequately dissipating the heat generated thereby.
Still another object of the present invention is the provision for cooling the electronic components of an air conditioning control box in an effective and economical manner.
These objects and other features and advantages become more readily apparent upon reference to the following description when taken in conjunction with the appended drawings.